Should people be paid for donating blood? In the United States, there is a mixed economy of free donation and the sale of blood through commercial blood banks. Predictably, most of the blood that is dealt with on a commercial basis comes from the very poor, including the homeless and the unemployed. The system entails a large-scale redistribution of blood from the poor to the rich.

This is only one of the examples cited by Michael Sandel, the political philosopher and former Reith Lecturer, in his survey of the rapidly growing commercialisation of social transactions, but it is symbolically a pretty powerful one. We hear of international markets in organs for transplant and are, on the whole, queasy about it; but here is a routine instance of life, quite literally, being transferred from the poor to the rich on a recognised legal basis. The force of Sandel’s book is in his insistence that we think hard about why exactly we might see this as wrong; we are urged to move beyond the “yuck factor” and to consider whether there is anything that is intrinsically not capable of being treated as a commodity, and if so why.